20904379 has 4 divisors (see below), whose sum is σ = 20916576. Its totient is φ = 20892184.

The previous prime is 20904343. The next prime is 20904391. The reversal of 20904379 is 97340902.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20904379 - 2⁷ = 20904251 is a prime.

It is a super-2 number, since 2×20904379² = 873986122751282, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20904319) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3004 + ... + 7129.

It is an arithmetic number, because the mean of its divisors is an integer number (5229144).

Almost surely, 2^20904379 is an apocalyptic number.

20904379 is a deficient number, since it is larger than the sum of its proper divisors (12197).

20904379 is a wasteful number, since it uses less digits than its factorization.

20904379 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12196.

The product of its (nonzero) digits is 13608, while the sum is 34.

The square root of 20904379 is about 4572.1306849214. The cubic root of 20904379 is about 275.4730326930.

The spelling of 20904379 in words is "twenty million, nine hundred four thousand, three hundred seventy-nine".